1. Field of the Invention
The present invention relates to a system for identifying individuals by comparing an input image with a dictionary image previously stored.
2. Related Art
A technology is well known by which an individual is identified from physical information (about the face, iris and fingerprints, for example) of human beings and other animals. To cite an example, this technology is disclosed in U.S. Pat. No. 5,291,560.
In the technology revealed in the above literature, the image of the iris of an eye of a human being is converted into codes of 0 and 1, and the codes are stored as a dictionary. In an actual identification process, an input iris image is converted into codes of 0 and 1, and the codes are compared with codes stored in the dictionary to establish the identity of an individual.
By the conversion of an input image into codes of 0 and 1, the amount of processing can be reduced, which leads to savings of storage capacity. In the identification of an individual by fingerprints, too, it is ordinary to detect the features from an input image, and store only data on the features as a dictionary. Likewise, in the identification of an individual by a face image, the amount of information is reduced by the use of mosaic images or the facial features.
In the conventional technology mentioned above, however, the input image is converted into codes of 0 and 1 or information about the facial features. Therefore, if the system should make an error in understanding data, it is difficult for a user without specialized technical knowledge to find the cause of the problem, the system will be a burden for the user to deal with.
To take an identification system using the face as an example, if a smiling face is registered when a dictionary is created and a serious face is input in the actual operation of the system, the system may mistake this as a discrepancy in the comparison step. On the other hand, if days passed from the registration till the identification operation and the user forgot his or her facial expression on the day of registration, it is impossible to conduct identification by simply displaying the registered image and the input image for comparison, with the result that it is impossible to decide whether the identification itself is correct or wrong.
In a system which has images at the time of dictionary creation stored in advance, if a misidentification occurred, even when the stored image at issue is displayed, it takes time until you can find that region from the image of the whole face which was conducive to the misidentification.
Accordingly, it has long been desired that a system should be developed which enables the user to find the cause of the misjudgment even when misidentification occurred.
With a system for identifying individuals by the prior art mentioned above, when this system is applied to identification of animals, such as dogs, cats or horses, a problem arises as follows.
Animals are different from human beings and you cannot expect them to behave in a manner favorable to the system. For example, when taking a picture of the iris of the eye with a video camera, a person is at a standstill squarely facing the camera. However, in the case of an animal, it does not look at the camera, and the face is moving most of the time.
Therefore, in the identification of animals, the images taken are inferior in picture quality, which is often responsible for a failure of identification. For this reason, it was necessary to take images repeatedly.
In this respect, it has been expected that a system for identifying individuals should be created which can identify an individual even when the image obtained does not have a good picture quality.
To solve this problem, the present invention adopts the following arrangement.
According to a first aspect of the invention, a system for identifying individuals comprises:
an image memory means for storing an input image of a individual as an object to be identified;
a dictionary for having data on the features of collation objects stored in advance;
a dictionary image memory means for storing dictionary images as a basis on which to extract data on the features of the collation objects;
an individuals identification means for analyzing the input image held in the image memory means and comparing said data on the features stored in the dictionary to thereby identify the individual;
an identification result analysis means for analyzing the identification result by the individuals identifying means and detecting that area of the region used for identification in the input image which does not agree with the dictionary data;
a result output control means for, according to identification result by the individuals identifying means, issuing an analyze command to the identification result analysis means and, according to analysis result by the identification result analysis means, issuing a command to display the discordant portion to the identification result analysis means, and deciding whether or not to display the input image and the dictionary image;
an image output control means for, according to a result of decision by the result output control means, controlling display of the discordant portion, the input image and the dictionary image; and
a display for displaying an image outputted by the image output control means.
With regard to the first aspect, the input image and the dictionary image are images of the iris of the human eye, and the individuals identifying means conducts identification by comparing iris codes. However, any arrangement other than was described above may be applied so long as it identifies an individual.
With continuing reference to the first aspect, the identification result analysis means detects an area where the input image does not coincide with the dictionary image by comparing iris codes, for example. The result output control means makes a decision to have at least where the discrepancy occurred displayed according to an analysis result of the identification result analysis means.
By this operation of the first aspect, even if the identity of the person is not established, where the discrepancy occurred is displayed, so that it is possible for the user to easily guess the cause of misjudgment.
It may be provided that, if the input image agrees with the dictionary data to such an extent that the identification result of the individuals identifying means is larger than a predetermined threshold value, the result output control means makes a decision not to issue an analyze command to the identification result analysis means nor issue a display command to the image output control means.
The rationale is that, if the input image agrees with the dictionary data to such an extent that the identification result of the individuals identifying means is larger than the predetermined threshold value, this means that the person is identified as a correct person. In this case, the system does not display analysis of the identification result nor display the input image. Therefore, unnecessary processing is not executed and a reduction of processing load can be expected.
It may be provided that, if the input image agrees with the dictionary data to such an extent that the identification result of the individuals identifying means is higher than the predetermined first threshold value but the amount of agreement is smaller than a second threshold value, which is smaller than the first threshold value, the result output control means makes a decision not to issue an analyze command to the identification result analysis means nor issue a display command to the image output control means.
Here, the analyze process and the image display process are not executed when the person is identified as a correct person or the person is identified as somebody else or the quality of the input image is judged to be inferior, and the analyze process and the image display process are executed only when the identity of the person is uncertain. The cases where the degree of agreement between the input image and the dictionary data is less than the second threshold value include a case of no agreement at all.
By this arrangement, unnecessary processing can be omitted and security can be secured even if a different person in bad faith attempts to use the system.
If the identification result analysis means analyzes and judges the discordant portion between the input image and the dictionary image to be larger than the predetermined value, it may be provided that the result output control means judges that the input image, for the most part, differs from the dictionary image and makes a decision to cause the input image to be displayed.
The upshot of this is that according to the result of the analyze process by the identification result analysis means, if the result output control means judges that the input image, for the most part, differs from the dictionary data, only the input image is displayed. In other words, in this case, the dictionary image is not displayed. Therefore, if the image is out of focus or blurred, the user can easily guess the cause of misjudgment by looking at the input image. Furthermore, even when an ill-intentioned person tries to use the system, security can be maintained.
According to a second aspect of the invention, system for identifying individuals comprises:
an image memory means for storing an input image of an individual to be identified;
a dictionary for having data on the features of collation objects stored in advance;
a dictionary image memory means for storing dictionary images as a basis on which to extract data of the features of the collation objects;
an individuals identifying means for analyzing the input image held in the image memory means and comparing the data on the features of the dictionary to thereby identify the individual;
an identification result analyzing means for analyzing the identification result by the individuals identifying means and detecting that area of the region used for identification in the input image which does not agree with the dictionary data; and
a result output control means for making a decision not to display any image on the basis of a judgment that the input image, for the most part, differs from the dictionary data if the discordant person is larger than a predetermined value in the analysis of the identification result analysis means.
The upshot of the second aspect is that as the result of the analyze process by the identification result analysis means, if a decision is made that the input image, for the most part, differs from dictionary data, no image is displayed. In this case, for example, when an ill-intentioned person tries to access the system, security is preserved because no input image is displayed and it is least likely to be known how identification of an individual is carried out. This invention is suitable for cases where emphasis is placed on the preservation of security.
It may be provided that the result output control means makes a decision to cause both the input image and the discordant portion to be displayed if it is judged in the analysis by the identification result analysis means that the input image partially differs from the dictionary image when the discordant portion is smaller than a predetermined value.
The upshot of this is that both the discordant portion and the input image are displayed in cases of identification by the iris in which the input image is a correct person""s but there is a partial difference between the input image and dictionary data when the iris is hidden behind the eye lid or eyelashes or light is reflected by the eye to the camera. Thus, the above images serve as an effective clue by which to guess the cause of misjudgment by the user. If an operator attends the system, he can make a final decision on the basis of the above images.
It may be provided that the result output control means makes a decision to cause only the discordant portion to be displayed on the ground that the input image partially differs from dictionary data when the discordant portion is smaller than a predetermined value in the analysis by the identification result analysis means.
The upshot of this is that only the discordant portion is displayed, instead of displaying both the input image and the discordant portion. This offers an effective clue by which to guess the cause for the user to be unable to make a correct apprehension. If an operator attends the system, the above images serve as a basis on which he makes a final decision.
It may be provided that the object to be identified is the iris in the eye. Thus, individuals can be identified by collation of iris images. Furthermore, it is possible to guess the cause of a misidentification, such as the iris being hidden behind the eyelid or eyelashes or the reflection of light by the eye to the camera which hampers identification even when an input image or a correct person is used.
According to a third aspect of the invention, a system for identifying individuals comprises:
a recognition dictionary for having stored in advance data on features of an object to be identified and additional information peculiar to the object obtained from the object to be identified;
an individuals identifying means for identifying an individual by comparing the data on features of the object to be identified with data on features of the dictionary data;
an identification result decision means for, when having made a decision not to input additional information in a decision regarding whether or not to input additional information according to identification result by the individuals identifying means, outputting identification result by the individuals identifying means as a final result, or, when having made a decision to input additional information, issuing a command to obtain additional information and also a command to conduct a re-identification process according to a result of the re-identification process, and making a decision to terminate the re-identification process according to a result of the re-identification process, and outputting a final identification result;
an additional information inputting means for obtaining arriving additional information upon receiving additional information from the identification result decision means; and
a re-identification means for, on receiving a command to conduct a re-identification process from the identification result decision means, selecting the identification dictionaries containing all of additional information acquired by additional information inputting means, and outputting as the result of re-identification a dictionary having a closest possible value to data on the features of the object under identification among selected dictionaries.
With regard to the third aspect, the individuals to be identified may be human beings or animals, such as dogs, cats and horses. And, individuals of any other kind may be identified. Among the methods for identifying individuals, there is the iris identify process using the iris of the eye. However, any other method may be used. Furthermore, additional information is about the external features of the object under identification, such as the distinction of sex, the color of the eye, etc. Any other kind of information, such as audio information, may be used so long as individuals have a peculiar and common feature.
With continuing reference to the third aspect, the individuals identifying means conducts an identification process on an individual, the results of which are outputted to the identification result decision means. When the individual is identified as a correct individual according to the identification result of the individuals identifying means, the identification result decision means outputs this information as the final identification result. On the other hand, if the individual is not identified as a correct individual, the re-identification command is issued which is added with additional information. Additional information input means obtains additional information entered by the user or operator, and on the basis of this information, the re-identification means executes a re-identification process. By using the re-identification result by the re-identification means, the identification result decision means, if accordingly the individual could be identified, for example, outputs a decision to terminate the re-identification process along with a final identification result.
Therefore, even if the identification of the individual failed in the individual identification process, re-identification is performed focusing on certain dictionaries by using additional information, so that identification of an individual is still possible even when an obtainable image has a poor picture quality.
It may be provided that the dictionary has a number of different items of additional information stored in advance, and that the re-identification means conducts a re-identification process each time it receives one item of additional information obtained by additional information input means.
The upshot of this is that additional information may be a plurality of items of information, such as the distinction of sex, the hair color, and the re-identification means may conduct a re-identification process each time it receives one item of additional information. Therefore, the re-identification process can be carried out even if all items of information are supplied, and superfluous input operations need not be performed.
It may be provided that the identification result decision means makes a decision to terminate the re-identification process each time the re-identification means conducts a re-identification process.
The upshot of this is that a decision may be made to terminate the re-identification process each time one item of additional information is input. Therefore, when the person has been identified by input of any additional information, it is not necessary to any more re-identification process, so that time spent for identification can be shortened.
It may be provided that the identification result decision means changes a criterion for re-identification at each execution of the re-identification process by the re-identification means.
The upshot of this is that the threshold value may be varied to ease the criterion, for example, at each re-identification process. Therefore, it becomes possible to enhance the probability of successful identification of an individual while suppressing a deterioration of identification accuracy.
It may be provided that the identification of an individual is by collation of iris images and that the additional information is about the external features of the individual.
The upshot of this is that the process for identifying an individual is done by collation of iris images and additional information is about the external appearance of an individual under identification. Therefore, even if an obtained image of the eye is inferior in picture quality, identification may succeed. Because the additional information is about external features, even if the operator is supposed to confirm the entered additional information, the operator can confirm it easily with fewer errors.
According to a fourth aspect of the invention, a system for identifying individuals comprises:
an image output unit for taking pictures of an individual as an object to be identified from different camera angles and inputting images of the object;
an image analyzing means for analyzing the image and extracting the features of the external appearance of the object; and
an output unit for obtaining a name by which to identify an individual under identification according to the features.
It may be provided that the image analyzing means extracts the features by selecting a name of a feature corresponding to the image for each of the elements of external appearance out of the names of predetermined features allotted to variations of respective elements of the external appearance.
It may be provided that the fourth aspect of the invention further includes a data base of data representing the features of the external appearance of a plurality of individuals by the names of features, the data being associated with the names of the individuals when the data is accumulated, wherein the output unit is so arranged as to search the database, and obtain the names of individuals having the names of features corresponding to the names of features selected at the image analyzing means as the names of individuals under identification.
It may be provided that the individuals to be identified and the plurality of objects are animals, and that the elements of the external appearance, which are used in the image analyzing means, the database and the output unit, are two or more items of the fur color, the white patterns of the head, the location of whirls, and white marks of the legs.
It may be provided that the image analyzing means extracts not less than two items of the location of a scar of an animal under identification and the condition of spots other than white marks, that the database is associated with the names of the plurality of animals, the location of scars or the condition of spots of each animal when data is accumulated, and that the output unit searches the database using the location of the scar or the condition of spots extracted from the image to thereby obtain the name of the animal to be identified.
According to the fifth aspect of the invention, a system for identifying individuals comprises:
a name input means for entering the name of an individual under identification;
an image input unit for inputting images of an individual under identification by taking images of the object;
an image analyzing means for analyzing the image and extracting the features of the external appearance of an individual under identification;
a data base for accumulating data representing the features of the external appearance of individuals associated with the names of a plurality of individuals, and searching data corresponding to the names input through the name input means to thereby output the data; and
a true/false decision unit for making a decision of whether an individual under identification is true or not by comparing the features found at said data base with the features extracted by said image analyzing means.
It may be provided that the image analyzing means extracts the features by selecting a name of a feature corresponding to the image for each of the elements of external appearance out of the names of predetermined features allotted to variations of respective elements of the external appearance.
It may be provided that the data base is accumulated in such a way that items of data on the features of the external appearance of the plurality of individuals are associated with the names of the individuals, the items of data being represented by the names of the features, and that the true/false decision unit makes a decision of whether an individual under identification is true or not by comparing names of the features found at the data base with names of the features extracted by the image analyzing means.
It may be provided that the individuals under identification and the plurality of individuals are animals and that the elements of the external appearance, which are used in the image analyzing means, the database and the output unit, are two or more items of the fur color, the white patterns of the head, the location of whirls, and white marks of the legs.
It may be provided that the image analyzing means extracts not less than two items of the location of a scar and the condition of white marks of an animal under identification, the database associates the names of the plurality of animals with the condition of scars of each animal or the condition of spots when accumulating data, and the true/false decision unit makes a decision of whether the animal under identification is true or not from the location of scars or the condition of spots extracted from the image.
It may be provided that the image input unit is formed by a plurality of cameras, disposed around the object under identification, for taking images of the object under identification.
It may be provided that the image input unit is formed by a camera movable around an individual under identification to take images of the object under identification.